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The PVSDM model was used for single and binary dye adsorption systems. This model is commonly used for adsorption in single systems, but this is the first time used in a binary mixture of dyes in the literature. To that end, a new adsorbent derived from Bauhinia forficata waste was created and described for eventual use in the treatment of a dye combination (methylene blue and crystal violet). The single and binary isotherms revealed that increasing the temperature decreases the methylene blue adsorption capacity while increasing the crystal violet adsorption capacity. The Langmuir and extended Langmuir models described the single and binary systems, respectively. Maximum adsorption capacities of 229.13 mg g−1 at 298 K for methylene blue and 324.12 mg g−1 at 328 K for crystal violet were obtained. The thermodynamic parameters showed that the adsorption process for both dyes is spontaneous, being exothermic for the methylene blue and endothermic for the crystal violet. Similar decay curves for the single and binary systems were observed. The PVSDM was able to describe both single and binary adsorption systems. The external mass transfer and the surface diffusion change according to the initial dye concentration and the system type (single or binary). [Display omitted] • The capacity of the single systems was 190.9 and 267.7 mg g−1, for the MB and CV. • The capacity for the mixture was 185.51 and 266.6 mg g−1 for the MB and CV. • The PVSDM model was able to describe the adsorption of single and binary systems. • The external mass transfer and surface diffusion changed according to the system. [ABSTRACT FROM AUTHOR]

This article investigated the recovery of Gd3+ from real leachate of phosphogypsum (PG) using natural bentonite clay. Firstly, a detailed adsorption study was performed using synthetic Gd3+ solutions. Then, it was investigated the clay performance in the real PG leachate. The characterization results indicate classical bentonite characteristics, such as rugosity and an S BET 91.3 m² g−1, with meso (D p =3.82 nm) and macroporous (D p =52.6 nm). In addition, it was identified that the major functional groups are hydroxyl and silicate, with the presence of organic matter. The initial pH solution effect indicates that the optimum removal of Gd3+ is at pH (6), attributing to the pH pzc being at 5.75 and the negatively charged surface above the pH pzc. The Avrami fractional order model was the most suitable for describing the experimental kinetic data. The Langmuir was the proper model for describing the adsorption isotherms, indicating that the Gd3+ forms a monolayer at the surface of the bentonite. The maximum adsorption capacity at pH 6.0 was 121.5 mg g−1. The thermodynamic parameters indicate that the adsorption is spontaneous, with a standard enthalpy change of − 92.30 kJ mol−1, indicating an ionic exchange, where the Gd3+ tends to be organized at the surface, according to the standard entropy change of − 206.0 J K−1 mol−1. The fixed bed adsorption test showed that Gd3+ could be adsorbed for up to 200 min without regeneration. Regeneration results show that the citric acid is more efficient in desorbing the Gd3+ from the bentonite, reaching up to 8 cycles without efficiency loss. Finally, the bentonite clay could selectively recover Gd3+ from the real PG leachate. • Selective adsorption of gadolinium from leachate using bentonite. • The specific ion-exchange mechanism between bentonite and Gd+3. • Bentonite could be used for 8 adsorption-desorption cycles. • Bentonite could selectively recover 90% of Gd3+ from the leachate. [ABSTRACT FROM AUTHOR]

The porous structure of ZSM-5 zeolite strongly affects the adsorption, especially when resistant compounds are present in the water, such as naphthenic acid in oil-produced water. In this sense, ME-ZSM-5 zeolite was synthesized by adding sodium alginate for later use as an adsorbent to remove naphthenic acid from synthetic water and real oil-produced water. Firstly, the results showed that the structural characteristics of the modified zeolite were improved by using sodium alginate (surface area of 235.58 m2 g−1 and total pore volume of 0.125 cm3 g−1). Besides, the adsorption of naphthenic acid from synthetic water was optimal using an adsorbent dosage of 3 g L−1 and pH 4, being the adsorption capacity of 195 mg g−1. Still, in synthetic solutions, the enthalpy of adsorption confirmed an exothermic process, and kinetic studies showed that the system reached equilibrium within the first 50 min. Finally, ME-ZSM-5 was applied to remove naphthenic acid from a real sample of oil-produced water and removed 92%. Therefore, ME-ZSM-5 zeolite was successfully synthesized and could be used as adsorbent material to uptake naphthenic acid from oil-produced water. [Display omitted] • ME-ZSM-5 zeolite was synthesized to treat oil-produced water from offshore. • ME-ZSM-5 could be used to uptake naphthenic acid from oil-produced water. • The maximum adsorption capacity was 195 mg g−1 at 298 K. • The adsorption equilibrium occurred within 50 min. • The efficiency in treating real oil-produced water was 92%. [ABSTRACT FROM AUTHOR]

The seed pods of the forest species Erythrina speciosa were pyrolyzed with ZnCl 2 to obtain porous activated carbon (Ery-AC) for adsorption purposes of Ibuprofen. The new material was microporous with a surface area of 795 m2 g-1. The kinetic and isothermal studies were conducted at a pH of 3 and an Ery-AC dosage of 0.75 g L-1. The Freundlich and Langmuir isotherms fitted the equilibrium curves, being the adsorption capacity of 98.11 mg g-1. Studies confirmed the endothermic nature (ΔH0 =27.36 kJ mol-1). System equilibrium was reached at around 100 min. The linear driving force (LDF) model fits the data satisfactorily. Besides, Ery-AC was tested on a simulated effluent containing various pharmaceutical compounds, presenting a removal efficiency of 65.54 %. The new activated carbon was tested to remove Ibuprofen from water in concentrations of μg L-1 and presented excellent results (95 % of removal). Last, regeneration revealed that the Ery-AC could be used 7 times. Therefore, applying seed pods of the forest species Erythrina speciosa carbonized with ZnCl 2 is highly efficient in removing Ibuprofen and mixtures with other pharmaceuticals. [Display omitted] • Porous activated carbon from seed pods of Erythrina speciosa. • Adsorption of Ibuprofen. • The surface area was 795 m2 g-1, and the adsorption capacity was 98.11 mg g-1. • The activated carbon can be reused 7 times. [ABSTRACT FROM AUTHOR]

Biochar was produced from the sawdust of the wood forest species Cedrella fissilis and later used as an adsorbent to remove atrazine herbicide from aqueous media. Biochar showed high thermal stability, an amorphous structure, and a highly irregular surface, mainly composed of carbon-containing bonds. The isothermal curves confirmed that the increase in temperature favored the adsorption of the herbicide. The Langmuir model best suited the experimental equilibrium data, with the maximum adsorption capacity of 7.68 mg g-1 at 328 K. The thermodynamic parameters confirmed a spontaneous process of an endothermic nature governed by physical interactions (interactions of van der Waals and hydrogen bonds). Kinetic studies showed that equilibrium was reached within 180 min. The linear driving force model (LDF) showed good statistical adjustment to the experimental data, where it was observed that the diffusion coefficient increased with the concentration of adsorbate. Biochar can be reused in up to three cycles. Finally, the adsorbent showed good efficiency in real water samples from rivers contaminated with atrazine, with 76.58% and 71.29% removal. [Display omitted] • Biochar was produced from the sawdust of the wood forest species Cedrella fissilis. • The biochar was used to remove atrazine herbicide from aqueous media. • n–π, π –π and H-bonds were the main interactions between atrazine-biochar. • The maximum adsorption capacity was 7.68 mg g-1. • The biochar showed good efficiency in real water samples from rivers. [ABSTRACT FROM AUTHOR]

The pitaya peel (Hylocereus undatus) was carbonized in the presence of ZnCl 2 to obtain a carbon-based adsorbent to remove the Metanil Yellow dye (MY) from colored waters. The characterization techniques confirmed that the material had morphological changes with the appearance of new irregularities and cavities. Besides, the alternative adsorbent was formed mainly by carbon and functional groups characteristic of lignin and cellulose. Isothermal and kinetic studies were carried out at the natural pH of the solution at a dosage of 0.4 g L−1. The Langmuir model demonstrated the best adjustment of the equilibrium isotherms of the system, reaching the maximum adsorption capacity of 144.07 mg g−1 at 298 K. The thermodynamic behavior indicated that it is a spontaneous and favorable process of an exothermic nature (Δ H 0 =−34.02 kJ mol−1), consistent with a mechanism involving electrostatic interactions. The MY concentration influenced the kinetic. The homogeneous surface diffusion model (HSDM) showed good statistical adjustment to the kinetic values, showing a slight increase in the diffusivity coefficient from 2.4 × 10−9 to 4.5 × 10−9 cm2 s−1 with the increased MY concentration. The material application in a mixture containing several dyes and salts in the circumstances close to the real ones showed removal of 82.5%. The adsorbent could be regenerated and used 12 times. Therefore, it can be concluded that the pitaya fruit residual biomass can be used as a precursor for preparing carbon-based adsorbents. The adsorbent, in turn, is a promising alternative in the treatment of MY dye and mixtures of organic molecules. [Display omitted] • A microporous carbon-based adsorbent was developed from pitaya peels. • The adsorbent was efficient in uptake Metanil Yellow dye from effluents. • Maximum adsorption capacity was 144.07 mg g−1. • Excellent adsorption performance in simulated effluents. • The material can be used 12 times. [ABSTRACT FROM AUTHOR]

A novel Fe-Al-La composite adsorbent was synthesized via the co-precipitation method for water defluorination. The adsorbent was characterized by XRD, BET, SEM/EDS, and FT-IR. Its adsorption behavior was thoroughly carried out to investigate the fluoride removal performance in synthetic and real groundwater samples. The Langmuir model was found to describe the adsorption isotherm, presenting a maximum adsorption capacity of 28.06 mg g−1 at 298 K and pH = 8.25. The adsorbent material's fluoride removal performance can be associated with the synergistic effect of some properties such as amorphous structure, porosity, and Fe-Al-La interactions in the surface material. The linear driving force model was successfully used for describing the adsorption capacity with a surface diffusion ranging from 3.52 to 5.928 × 10–9 cm2 s−1. Results showed that the new composite might be applied to remove fluoride from water aiming at human consumption, achieving the established permissible limit for Water Health Organization (< 1.5 mg L−1). [Display omitted] • A novel Fe-Al-La composite was prepared by chemical route. • Fe-Al-La presented high removal performance of fluoride in water. • The maximum adsorption capacity of 28 mg g−1 at 298 K and natural pH = 8.25. • Synergism contributed to its high adsorptive performance. [ABSTRACT FROM AUTHOR]

In this work, a high porous activated carbon from Jacaranda mimosifolia was developed and employed for ketoprofen adsorption. After the pyrolysis process at 973.15 K, the material presented cavities with different sizes allocated on the particle surface. The material presented a pH at the point of zero charge of 4.1 with the best adsorption at pH 2. The best adsorbent dosage was 0.72 g L−1, corresponding to a removal of 96%. The system reached the adsorption equilibrium after 120 min and was described by the linear driving force model. The isotherms revealed that the adsorption capacity decreased with the temperature and followed the Langmuir model, with a maximum adsorption capacity of 303.9 mg g−1. This high capacity can be associated with the high surface area (928 m2 g−1) and pore volume (0.521 cm3 g−1) values. The thermodynamic values indicated that the adsorption system is spontaneous and exothermic. The enthalpy value indicates that the interactions between the adsorbent and adsorbate are physical. Regeneration tests showed a decreasing percentage of removal of 7.86% after 5 cycles. Finally, the adsorbent showed efficiency when treating a simulated effluent containing drugs and inorganic salts, showing the removal of 71.43%. [Display omitted] • Jacaranda-derived activated carbon was prepared by pyrolysis and activation process. • Activated carbon with high surface area and pore volume was produced. • The high adsorption capacity for aqueous-phase ketoprofen was observed. • Surface diffusion was found to range from 7.14 × 10−9 to 9.80 × 10−9 cm2 s−1. • Physical adsorption was the mechanism involved in the adsorption process. [ABSTRACT FROM AUTHOR]

Carbon nanotubes with multiple walls (MWCNTs) were modified via green synthesis methodology, with metal nanoparticles (MPNs-Fe). The prepared material (MWCNT/MPNs-Fe) was characterized and used to remove the herbicide glyphosate (GLY) from an aqueous matrix through the adsorption process. The characterization results indicated the presence of MPNs-Fe incorporated between the tangled wires of the MWCNTs, thus confirming the green synthesis success. The kinetic studies showed a percentage of GLY removal of up to 86.23% (for C 0 = 35 mg L−1), with the process equilibrium being reached in 120 min. The pseudo-first-order model demonstrated a greater prediction capacity for the system. The Sips isotherm model was best suited to the equilibrium data, providing a maximum adsorption capacity of 43.66 mg g−1 (298 K). The thermodynamic behavior showed that the process is spontaneous and favorable, with exothermic nature. The material's application in close to real circumstances presented the removals of 68.38% and 40.33% for two simulated effluents with different compositions. The adsorption regeneration tests found that the adsorption kept similar adsorption capacities after six cycles. Therefore, it can be concluded that the MWCNT/MPNs-Fe synthesized in the present work is a promising alternative as an adsorbent in the treatment of effluents and waters containing GLY. ga1 • An adsorbent was developed by impregnation of Fe nanoparticles on carbon nanotubes. • The adsorbent MWCNT/MPNs-Fe was prepared by green synthesis. • MWCNT/MPNs-Fe was applied in glyphosate adsorption. • Glyphosate removal of up to 86% was reached in 120 min. [ABSTRACT FROM AUTHOR]

In this work, an activated carbon sample with a high adsorptive performance for the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) was prepared from queen palm endocarp (Syagrus romanzoffiana) by pyrolysis process. The activated carbon presented an XRD pattern related to carbon graphite and functional groups such as C–H, C˭O, O–H. The material particles presented a highly-porous structure, being beneficial to the adsorption process. The activated carbon showed a remarkable specific surface area of 782 m2 g−1 and pore volume of 0.441 cm3 g−1. The solution pH presented a strong influence on the adsorption process, with ideal pH = 2, being the best adsorbent dosage, 0.5 g L−1. The correspondent removal percentage was 95.4%. The pseudo-second-order model represented kinetic data, presenting R2 > 0.992 and MSR< 19.62 (mg g−1)2. The Langmuir model was the most suitable for describing the equilibrium data with the highest R2 (> 0.997) and lowest values of MSR (< 92.04 (mg g−1)2), indicating a maximum capacity of 367.77 mg g−1. The thermodynamic study indicated a spontaneous operation, with ΔG0 ranging from –23.2 to −32.6 kJ mol−1 and endothermic process (ΔH0 = 67.30 kJ mol−1), involving physical interactions in the adsorbent/adsorbate system. The adsorbent could be regenerated by NaOH and used 7 times with the same adsorption capacity. Hence, overall, the activated carbon prepared from the Jerivá endocarp corresponds to a promising adsorbent in removing 2,4-D herbicide in wastewater. ga1 • Activated carbon from Queen palm fruit endocarp was prepared. • The material presented high-performance to adsorb 2,4-dichlorophenoxyacetic. • Specific surface area was 782 m2 g−1 and pore volume was 0.441 cm3 g−1; • The maximum adsorption capacity was 367.77 mg g−1; • The adsorbent could be used 7 times with the same adsorption capacity. [ABSTRACT FROM AUTHOR]

• Eco-friendly strategy for groundwater defluorination. • Adsorption on calcinated sludge. • Process was efficient at pH of 5.5, and using 5 g L−1 of calcinated sludge. • The groundwater attained the WHO standard within 60 min. • The maximum adsorption capacity was 2.04 mg g−1. The excess of fluoride ions (F−) in water for human supply is a serious public health. The recommended concentration of F− ions by the World Health Organization (WHO) is 1.5 mg L-1. Several groundwater sources around the world contain high F− concentrations, and require treatment before human consumption. It was developed an eco-friendly and low-cost strategy for groundwater defluorination, i.e., adsorption onto calcinated sludge. This strategy was efficient at pH of 5.5 and using 5 g L-1 of calcinated sludge. The groundwater attained the WHO standard within 60 min. The kinetic model of pseudo-second-order obtained a better adjustment to the experimental data. The equilibrium curve at 25 °C was better represented by the Tóth model. The maximum adsorption capacity was 2.04 mg g-1. Therefore, adsorption using calcinated sludge can be considered as an eco-friendly and low-cost strategy for groundwater defluorination. [ABSTRACT FROM AUTHOR]

The mass transport mechanism of the In(III) adsorption on chitin and chitosan was elucidated in this research. The chitosan and chitin presented specific surface area values of 3.60 and 4.30 m2 g−1, with average pore radius of 14.30 and 33.10 Ǻ, respectively. It was identified in chitosan and chitin, typical groups, such as N H and C O. It was found that both materials present a rigid surface without the presence of visible pores and cavities, with a geometry that resembles plates. Further analysis indicates the presence of the In(III) on the surface of both materials. The isotherm experiments indicated that the temperature caused an increase in the adsorption capacity for both materials. The Langmuir model was chosen for describing the equilibrium in both cases. The External Mass Transfer Model (EMTM) and Pore Volume and Surface Diffusion Model (PVSDM) were used for describing the indium concentration decay curves for the chitosan and chitin. Nevertheless, the modified Biot number (between 8.82 × 10−4 and 2.71) indicated that, in this case, the external mass transfer was the dominant mechanism. In addition, chitin and chitosan were efficient adsorbents for In(III), since that only 0.35 mg L−1 of In(III) remained in solution after adsorption. Chitosan provided faster adsorption kinetics, and this fact was attributed to its higher external surface area. The findings revealed that the overall mass transport mechanism is as follows: the indium species in the bulk solution are transferred to the adsorbent surface and then, adsorbed by surface precipitation and/or coordination bonds. • Mass transport mechanism of In(III) adsorption on chitin and chitosan was studied. • Biot numbers ranged from 8.82 × 10−4 to 2.71. • External mass transfer was the dominant mechanism. • Chitosan provided faster adsorption kinetics than chitin. • Surface precipitation and/or coordination bonds occurred during adsorption. [ABSTRACT FROM AUTHOR]

• Ten adsorbents were used to concentrate In(III) from real leachates. • The operation was analyzed by ANN and ANFIS. • ANN and ANFIS were able to predict the In(III) adsorption capacity. • Chitosan was able to concentrate indium from the LCD leachates. • Chitosan attained adsorption capacity of 1000 mg g–1 within 20 min of operation. Ten different adsorbent materials were tested to adsorb indium (III) from leachates of LCD screens, aiming to concentrate this valuable material. Artificial neural network (ANN) and adaptive neuro–fuzzy inference system (ANIFS) were applied to analyze the indium (III) adsorption. The input variables for the network models were: specific surface area, point of zero charge, adsorbent dosage and contact time. Adsorption capacity (q) was used as output variable. The adsorption capacity values ranged from 8.203 to 1000 mg g–1. The ANN modeling presented the best fit when the Levenberg–Marquardt algorithm was used. The ANFIS modeling presented the optimum performance when the hybrid method was used. Among the tested adsorbents, chitosan presented the best performance; attaining adsorption capacity of 1000 mg g–1 within 20 min. This is an excellent value since the maximum indium concentration in LCD screens is 0.613 mg g–1. This high capacity was attributed to the coordination ligation between chitosan and indium (III). [ABSTRACT FROM AUTHOR]

[Display omitted] • In-house chitin was used for the removal of Cd(II) at different temperatures. • The developed chitin presented classical groups reported in the literature, in special nonporous surface. • It was found that the system quickly reached equilibrium at 15 min for all the temperatures investigated. • Physical-statistical modeling indicates that the Cd(II) are adsorbed forming a monolayer. • Potential thermodynamic parameters were evaluated individually. This work analyzes the adsorption of cadmium, a potentially toxic pollutant, on biopolymers synthesized from shrimp shells, as a promising new adsorbent. Spectroscopic analysis, such as FTIR, ATD/ATG, XRD, and SEM/EDX techniques, were used to characterize chitin before it was exposed to cadmium ions. Experimental data indicate that Cd(II) adsorption proceeds with pseudo-second-order model kinetics and is influenced by increasing temperature. In the equilibrium, the maximum adsorption capacity obtained was 58.82 mg g−1 at a temperature of 308 K. Experiments to obtain adsorption data were performed at T = 298–318 K. The saturated adsorption capacities of Cd(II) range from 57.40 to 59.90 mg g−1. The application of the physics-statistics model indicates that the Cd(II) atoms are adsorbed on the surface of the chitosan forming a monolayer. In addition to that, the results also show that the adsorption affinity increases with the system temperature, resulting in higher affinity and an increase of 30% in the adsorption capacity. The adsorption energy was found to be around 2.5 kJ mol−1, indicating that the adsorption is physical and endothermic. The entropy was found to quickly increases (reaching a maximum value of 6 × 10−22 kJ mol−1 K−1) at low concentrations followed by the equilibrium after the 40 mg L−1, indicating that the equilibrium is quickly reached. The Gibbs free energy indicates that the process is spontaneous (ranging from −1.364 to −1.451 kJ mol−1) and that the energy tends to remain constant after 15 mg L−1. Last, the results indicate that the Cd(II) is adsorbed due to dipole–dipole interactions and possible coordination bounds. The results of tests on the adsorption of cadmium by chitin showed that this biopolymer could replace other more expensive adsorbents. [ABSTRACT FROM AUTHOR]

• Adsorption of potential toxic dyes (methylene blue and crystal violet) was studied. • A promising adsorbent was produced and tested during adsorption tests. • A physical model was applied on the entire adsorption data set. • Steric explanations supported a better understanding of the adsorption mechanism. • Two energies described the interactive effects of the adsorption systems. This paper analyzes the adsorption of two potential toxic dyes, i.e. methylene blue (MB) and crystal violet (CV) onto Bauhinia forficata residual fruit powder (BFRFP) as a new promising adsorbent. The experiments aimed at retrievement of adsorption data are carried out at T = 298–328 K and are coupled with an adsorbent characterization to better highlight the MB and CV dyes adsorption mechanism. MB adsorption capacity at saturation (ACS) varies from 181.48 to 201 mg.g−1, while for CV dye, it ranges from 263.06 to 282.61 mg.g−1. This difference is not very significant but reflects that the BFRFP has a higher affinity to remove CV dye. Comparing with some alternative adsorbents, the BFRFP adsorbent shows to be a competitive material for the removal of MB and CV dyes from polluted water. A model assuming that MB and CV dyes are removed via a formation of two layers on BFRFP is chosen as the one that, from a physical point of view, better interpret their adsorption mechanisms. The prediction of the number of dyes adsorbed on BFRFP is approximately equal to 1 for both the dyes, testifying that they are removed without an aggregation process and with slanted position. The physical model generates two energies to describe the interactive effects between both dyes and BFRFP adsorbent (dye- BFRFP) and between dyes (dye-dye). Results show that physical interactions occur during the adsorption process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Activated carbon (AC) from araçá fruit husks for atrazine adsorption. • It was a microporous material with a surface area of 431 m2 g−1. • The adsorption capacity was 35.67 mg g−1 at 328 K, and ΔH0 was 129.5 kJ mol−1. • Adsorption occurs due to electrostatic, H-bonds, π–π and n–π interactions. • The "araça" derived AC was promising in removing atrazine from aqueous solutions. The residual husks of the edible fruits of Psidium cattleianum were carbonized with FeCl 3 as an activating agent and used as an adsorbent to remove the toxic herbicide. After the carbonization step, changes in the material's structure were found. Activated carbon showed characteristics of microporous materials with a pore volume of 0.280 cm3 g−1 and surface area of 431 m2 g−1. Micrographs revealed the emergence of new cavities with a uniform and circular shape. The FTIR spectra showed the disappearance of some bands, remaining bands belonging to functional groups containing carbon, oxygen, and hydrogen. The XRD patterns confirmed the amorphous structure of the material even after the carbonization step, composed of amorphous graphitic carbon. EDS analysis showed that the carbon percentage increased and the oxygen decreased after the carbonization. The experiments were performed at neutral pH using 1 g L−1 of adsorbent. In equilibrium isotherms, the temperature played a considerable role in the adsorption capacity, increasing from 26.39 mg g−1 to 35.67 mg g−1 when the temperature varied from 298 to 328 K. The Liu isotherms were the ones that best fit the isotherm data. The changes in the adsorption enthalpy were endothermic (ΔH° 129.5 kJ mol−1). The general order kinetic model was the most adequate for kinetic data, presenting the lowest values of the Bayesian Information Criterion. Thus, activated carbon developed from the residues of the "araça" fruit showed promise in removing atrazine from aqueous solutions, with the great advantage of its high efficiency under neutral pH solutions and mild temperatures. [ABSTRACT FROM AUTHOR]

• Novel Hyper Cross-Linked Resin: ICYN-PPA, a new and cost-effective adsorbent synthesized in a single step from commercially available materials. • High Adsorption Capacity: ICYN-PPA exhibits a remarkable adsorption capacity of 112.8 mg g−1 for efficient removal of Bisphenol A from aqueous solutions. • Fast Kinetics: The system reaches equilibrium in just 350 min, showcasing the rapid adsorption kinetics of ICYN-PPA. • Thermal Stability: ICYN-PPA's exceptional thermal stability makes it a promising candidate for decontamination processes in BPA-containing effluents. • Environmentally Friendly Solution: ICYN-PPA offers a sustainable approach to mitigate Bisphenol A's harmful effects on human health and aquatic life, contributing to environmental preservation. The widespread utility of Bisphenol A (BPA) in the production of diverse plastic substances including mineral water bottles, food packets, toys, tickets, etc. leads to its release to the environment through industrial effluents that contaminate both the surface and underground water. Given its higher toxicity and harmful effects on both human health and aquatic life, the adsorption of BPA has been the subject of recent studies at present. Herein, we disclose the synthesis of a new hyper cross-linked resin (ICYN-PPA), derived from commercially available 3,3′-(piperazine-1,4-diyl)bis(propan-1-amine) and tris(2,3-epoxypropyl) isocyanurate in a single step reaction, and its adsorptive performance for the removal of BPA from aqueous solution. The thermally stable ICYN-PPA, which is porous and exhibits different sizes of particles on its surface, displayed optimum removal of BPA. The isothermal studies were well represented by the Koble-Corrigan model, where the capacity increased from 216.6 to 228.6 mg g−1 with an increasing temperature of 318 K. The linear driving force model (LDF) was efficient in representing the kinetic data. Whereas the system tends to reach equilibrium after 350 min. The surface diffusion coefficients were 1.301 × 10−16 and 1.859 × 10−16 cm2 s−1 for BPA adsorption on isocyanurate based hyper crosslinked resins. The thermodynamic parameters confirmed the endothermic nature of the process (ΔH0 = 35.83 kJ mol−1) based on physical interactions. [ABSTRACT FROM AUTHOR]

• A new adsorbent was prepared from the residue of Butiacapitate. • The adsorption of pharmaceutical molecules was studied. • Adsorption of ketoprofen was endothermic, while paracetamol was exothermic. • A double-layer model with two energies deriving from statistical physics was applied. • This study highlights the important aspects of the adsorption mechanism. This paper describes the removal process via adsorption of paracetamol (PRC) and ketoprofen (KTP) on activated charcoal prepared from the residue of the fruit of Butiacapitate. Some adsorbent characterizations are carried out for a plausible analysis of the adsorption results and for the description of adsorption mechanism. Modelling investigations show that the double layer derived from statistical physiscs can be adopted to interpret the adsorption data. Interestingly, the adsorption mechanism can be elucidated via the model parameters determined at different temperatures. The performance of the adsorbent in terms of maximum adsorption capacity increased from 101.16 to 134.52 mg/g for KTP molecules and decreased from 98.19 to 73 mg/g for PRC molecules, by increasing the temperature, which are in line with the experimental values retrieved. These tendencies of adsorption capacities may be related to the behavior of the number of PRC and KTP pharmaceuticals captured per functional group of the adsorbent. Overall, the modeling results show also that the values of adsorption energies associated to the two layers of KTP and PRC molecules on the adsorbent surface are lower than 40 kJ/mol, implying that only physical type interactions occur in the removal process of these pharmaceutical molecules. [ABSTRACT FROM AUTHOR]

In this paper, the adsorption of the herbicide 2,4-D and the drug ketoprofen on wheat husks Fagopyrum esculentum treated with H 2 SO 4 is experimentally and analytically analyzed. The adsorbent is fully characterized through some techniques such as FT-IR, SEM, and XRD. Adsorption tests are carried out to optimize the performances in terms of adsorbent dosage and solution pH. Subsequently, the impact of temperature is determined through the realization of adsorption isotherms. A multilayer model is employed to microscopically interpret the adsorption mechanism of both the investigated compounds. The modelling analysis shows that the number of molecules bound per adsorption site varied from 0.68 to 2.77 and from 2.23 to 3.59 for ketoprofen and herbicide 2,4-D, respectively. These estimated values testify that an aggregation process occurs during adsorption. The global number of formed layers of each adsorbate is also determined, showing a significant reduction from 5.73 to 2.61 for ketoprofen and from 1.79 to 1.5 for herbicide 2,4-D with the temperature. For a complete understanding of the adsorption mechanism, the saturation adsorption capacity and adsorption energy were calculated and interpreted. Overall, it may be inferred that physical interactions govern how these contaminants adsorb on the tested adsorbent. [Display omitted] • The adsorption of the herbicide 2,4-D and the drug ketoprofen was investigated. • The wheat husks Fagopyrum esculentum was employed as an adsorbent. • Application of physical adsorption model to ascribe new interpretations of the adsorption mechanism. • Description of the adsorption orientation of both pollutants. • Estimation and interpretation of adsorption energies. [ABSTRACT FROM AUTHOR]

[Display omitted] • New insights into glyphosate adsorption on modified carbon nanotubes; • Steric and energetic interpretations based on statistical physics models; • The adsorption occurs through the formation of a monolayer; • Intermolecular interactions between glyphosate molecules can be neglected; • Glyphosate adsorption occurs at MPNs-Fe present on the adsorbent. The present work used a statistical physics approach to present new insights into the adsorption of the pesticide glyphosate on modified carbon nanotubes via green synthesis (MWCNT/MPNs-Fe). The experimental equilibrium curves obtained for this system under pH 4 at temperatures 298, 308, 318, and 328 K were simulated from monolayer, double layer, and multilayer models, with 1 and 2 energies, considering real and ideal fluid approaches. Taking into account the statistical indicators and the physical meaning of the parameters, exploring simplifying hypotheses, the Hill model with 1 energy and ideal fluid approach (M1) presented the best prediction of the experimental data, indicating that glyphosate adsorption occurs by the formation of a monolayer and that pesticide interaction with MWCNT/MPNs-Fe are characterized by only one energy. Based on this approach, to assess the steric aspects of the system, the number of molecules adsorbed per site (n), the density of receptor sites (N m), adsorption capacity at saturation (Q sat), and concentration at half-saturation (W) were interpreted. As for the energetic aspects, the adsorption energy (ΔE) was inferred. The combination of parameters to its evolution with temperature and the magnitude of ΔE indicated an exothermic process involving a physical interaction mechanism. Finally, the new insights showed that the MWCNT/MPNs-Fe adsorbent favored pesticide adsorption by interacting glyphosate molecules with the metallic iron nanoparticles present on the adsorbent surface. [ABSTRACT FROM AUTHOR]